Chinese Elite Hacking Unit 61398

As Mandiant mapped the Internet protocol addresses and other bits of digital evidence, it all led back to the edges of Pudong district of Shanghai, right around the Unit 61398 headquarters. The group’s report, along with 3,000 addresses and other indicators that can be used to identify the source of attacks, concludes “the totality of the evidence” leads to the conclusion that “A.P.T. 1 is Unit 61398.”

Mandiant discovered that two sets of I.P. addresses used in the attacks were registered in the same neighborhood as Unit 61398’s building.

“It’s where more than 90 percent of the attacks we followed come from,” said Mr. Mandia.

The only other possibility, the report concludes with a touch of sarcasm, is that “a secret, resourced organization full of mainland Chinese speakers with direct access to Shanghai-based telecommunications infrastructure is engaged in a multiyear enterprise-scale computer espionage campaign right outside of Unit 61398’s gates.”